Saggar pin



W. W. IRWIN -SAGVGAR PIN I Nov. 18, 1941.

Filed 001;. 1%, 1940 INVENTOR.

BY -pw /wlm w WITNESSES.

flfl/fbxzw.

ATTORNEYS.

Patented Nov. 18, 1941 it UNlTEDT STATES PATENT owes I SAGGAR PINWilliam W. Irwin, East Liverpool, Ohio, assignor to The Potters SupplyCompany, East Liverpool, Ohio, a corporation of Ohio Application October16, 1940; Serial No. 361,349 4 Claims. (01. 25-453) This inventionrelates to saggar pins by which glaze-coated ceramic dinnerware and thelike is supported in saggars while being fired to vitrify the glaze. Asused herein the word saggar means any type of receptacle or rack inwhich ceramic ware is supported on saggar pins during firing.

The most practical type of saggar pin is one formed from ceramicmaterial extruded through a triangular die, as such a pin has much morestrength than a molded or cast pin of the same cross sectional area, andits triangular shape gives three well-defined points at each end, anyone of which may be used for engaging and supporting the ware. Theopening in the saggar wall which receives and supports the pin isusually inclined so that the ware will engage the pin at its upper pointonly and not along its upper edge.

As the ware is being fired,.the point of the pin is fused to it by theglaze which runs down the pin and forms a globular ring around it. Theportion of the pins pointed end that is embedded in this vitrified'ringof glaze breaks from the body of the pin when the ware cools or when itis lifted from the saggar. This leaves a hard, jagged piece of the pinprojecting from the bottom of the ware, and this piece must be chippedoff and the raised ring of glaze removed as well as possible before theware can be sold. It often requires considerable dressing to removethese marks from the ware, and in chipping off the adhering piece of pinthe ware is sometimes spalled, which makes it necessary to sell the wareas a second.

It is among the objects ofthis invention to provide a saggar pin whichleaves only a very small piece adhering to the fired ware,.which permitsthe formation of only a relatively small ring of glaze around itsware-supporting point, and which is as satisfactory and can bemanufactured as cheaply as the customary extruded saggar pins used atpresent.

In accordance with this invention a saggar pin, having a pointed end forengaging and supporting glaze-coated ceramic ware during firing, isprovided adjacent its pointed end with a recess which, by suddenlychanging the contour of the pin, limits to avery short distance thedistance the glaze will flow from the ware down around the pointed endportion of the pin. Preferably, this change in section or contour isformed by providing the side surfaces of the pin adjacent their lateraledges with grooves extending longiwill usually stop creeping downthe pinwhen it reaches the edges of the grooves nearest the ware,

and thus a smaller globule of glaze is formed which .can be removed moreeasily and satisfactorily.

The invention is illustrated in the accompanying drawing in which Fig. 1is a plan viewof a. saggar in which a plurality of plates are supportedby saggar pins; Fig. 2 is an enlarged fragmentary vertical section takenon the line IIII of Fig. 1; Fig. 3 is a still further enlargedfragmentary vertical section of a plate supported by a saggar pin andshowing them just after firing and before the plate has broken from thepin;

Fig. 4 is a perspective View of my saggar pin;

Fig. 5 is a fragmentary view of the bottom of a plate showing a ringofglaze around the point of a pin which has broken from the ware; andFigs. 6, 7 and 8 are end views of saggar pins made in accordance withthree different embodiments of this invention.

Referring to Figs. 1 and 2 of the drawing, a refractory saggar I of wellknown construction contains the usual two compartments each of which isadapted to receive a plurality of dinner plates 2 or the like thatpreviously have been coated with glaze and are to be fired in a kiln tovitrify the glaze. Each compartment of the saggar is provided in itsside wall with three vertical rows, substantially 120 apart, ofvertically spaced openings 3. Each opening is preferably triangular incross section with the base of the triangle at the bottom of the openingand with the axis of the opening inclined upwardly at an angle of about12. Inserted in each of these openings and projecting therefrom is aceramic saggar pin 4 that is triangular in cross section. The pinpreferably-is formed by extruding suitable ceramic material through atriangular die. The inner or upper ends of the pins at each level in thesaggar engage and support a plate on their uppermost points.

It is a feature of this invention that only a relatively small ring ofglaze forms around the adjoining end of each pin, so that the ware iseasily dressed and is not injured in removing the ring of glaze and thepoint of the pin adhering to it. Accordingly, close to the warethepointed end portion of the pin is reduced in cross section tointerrupt the smooth surface of the pin and thereby provide edges beyondwhich the molten glaze has little tendency to flow. For this purpose thepin is preferably provided with a plurality of grooves 5 extending fromend to end tudinally from end to end of the pin. The glaze along itsside surfaces adjacent their lateral edges. These grooves may be ofvarious shapes in cross section, as shown in Figs. 6, 7 and 8, and areeasily formed at no increase in manufacturing cost by providing the diethrough which the pin is extruded with projections of the desired sizeand shape. When the ware is fired and the glaze melts, it tends to rundown onto the pin and to thereby form a ring 6, as shown in Figs. 3 and5, but the distance this ring extends down on the pin is generallylimited by the upper edges of grooves 5 because the glaze seldom changesits direction of flow in order to pass around those edges and into thegrooves. Consequently, only a small globular ring of glaze forms aroundthe end of the pin, and this blemish can be removed much more easily andsatisfactorily than a large ring of glaze. With only a small, thin ringof glaze fusing the saggar pin to the ware, only a very small piece ofthe pin (Fig. 5) breaks from the ware after the glaze has solidified. Inchipping this point of the saggar pin from the ware there is littledanger of spalling the ware. If any of the glaze should happen to flowinto the grooves 5, it will run down them and therefore not increase thesize of the ring forming around the point of the pin. The grooves alsoweaken the point of the pin so that the portion of the pin that adheresto the ware will not break from the body of the pin at a point below thegrooves.

According to the provisions of the patent statutes; I have explained theprinciple and construction of my invention and have illustrated anddescribed What I now consider to represent its best embodiments.However, I desire to have it understood that, within the scope of theappended claims, the invention may be practiced otherwise than asspecifically illustrated and described.

I claim:

for firing, the side surfaces of said pin being:

provided adjacent their lateral edges with grooves extendinglongitudinally from end to end of the pin.

3. An elongated saggar pin having two side surfaces meeting along anedge extending lengthwise of the pin, said edge at at least one endthereof being adapted to engage and support glaze-coated ceramic ware ina saggar for firing, and each of said two side surfaces being providedclosely adjacent said edge with a groove extending lengthwise of the pinfrom the waresupporting end thereof.

4. An extruded saggar pin of substantially uniform cross section fromend to end and having a sharp edge extending lengthwise thereofthroughout its length to form a ware-supporting corner at each end ofthe pin, the surface of the pin being provided on both sides of saidedge and closely adjacent thereto with grooves extending from end to endof the pin parallel to said edge.

WILLIAM W. IRWIN.

